On 26 November at 0535 ZT, while taking sights for a morning fix, you observe an unidentified planet bearing 074° T at an observed altitude (Ho) of 38° 29.8'. Your DR position is LAT 27° 18.9' S, LONG 30° 18.4' E. The chronometer time of the sight is 03h 33m 16s, and the chronometer is 01m 48s slow. What planet did you observe?
• Using the chronometer time and correction to find the exact UTC of the sight • Determining which planet(s) are above the horizon at the given DR position, date, and time using the Nautical Almanac • Comparing the computed true bearing and altitude (Hc and Zn) for candidate planets with the observed bearing 074° T and altitude 38° 29.8'
• First convert the given chronometer time and its error into the correct UTC of the sight. What is the exact GMT you should enter the Almanac with? • From that time and your DR longitude, what is your approximate Local Hour Angle (LHA) of Aries, and which planets are in that part of the sky? • For each candidate planet, think about whether its calculated bearing and altitude from your DR could reasonably match a morning object at 074° T and about 38° altitude in late November in the Southern Hemisphere.
• Be sure you have applied the chronometer correction with the correct sign (it is slow vs fast). • Confirm which planets are actually visible in the morning sky on 26 November for your latitude, rather than just mathematically above the horizon. • Check that the computed bearing (Zn) for the planet you choose is reasonably close to the observed 074° T and that the altitude is in the right range for that object at that time.
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